Bsi bs en 15063 1 2014

NORME EUROPÉENNE ICS 77.040.20; 77.120.30 Supersedes EN 15063-1:2006 English Version Copper and copper alloys - Determination of main constituents and impurities by wavelength dispersiv

BSI Standards Publication

Copper and copper alloys

— Determination of main constituents and impurities

by wavelength dispersive ray fluorescence spectrometry (XRF)

X-Part 1: Guidelines to the routine method

National foreword

This British Standard is the UK implementation of EN 15063-1:2014

It supersedes BS EN 15063-1:2006 which is withdrawn

The UK participation in its preparation was entrusted to TechnicalCommittee NFE/34/1, Wrought and unwrought copper and copperalloys

A list of organizations represented on this committee can beobtained on request to its secretary

This publication does not purport to include all the necessaryprovisions of a contract Users are responsible for its correctapplication

© The British Standards Institution 2014 Published by BSI StandardsLimited 2014

ISBN 978 0 580 83960 3ICS 77.040.20; 77.120.30

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 December 2014

Amendments issued since publication

NORME EUROPÉENNE

ICS 77.040.20; 77.120.30 Supersedes EN 15063-1:2006

English Version

Copper and copper alloys - Determination of main constituents

and impurities by wavelength dispersive X-ray fluorescence

spectrometry (XRF) - Part 1: Guidelines to the routine method

Cuivre et alliages de cuivre - Détermination des éléments

principaux et des impuretés par spectrométrie de

fluorescence X à dispersion de longueur d'onde (FRX) -

Partie 1 : Lignes directrices pour la méthode de routine

Kupfer und Kupferlegierungen - Bestimmung von Hauptbestandteilen und Verunreinigungen durch wellenlängendispersive Röntgenfluoreszenzanalyse (RFA) - Teil 1: Leitfaden für das Routineverfahren

This European Standard was approved by CEN on 8 November 2014

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member

This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E F Ü R N O R M U N G

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

Contents Page

Foreword 3

Introduction 4

1 Scope 5

2 Principle 5

3 Terms and definitions 5

4 Instrumentation 7

4.1 Principles of X-ray fluorescence spectrometers 7

4.2 X-ray tubes 8

4.3 Vacuum system 9

4.4 Test sample spinner 9

4.5 Filters 9

4.6 Collimators of slits 10

4.7 Analysing crystals 10

4.8 Counters 11

4.9 Simultaneous and sequential Instruments 12

5 Sampling and test sample preparation 12

6 Evaluation methods 12

6.1 General 12

6.2 Dead time correction 12

6.3 Background correction 13

6.4 Line interference correction models 13

6.5 Inter-element effects correction models 13

7 Calibration procedure 14

7.1 General 14

7.2 Optimizing of the diffraction angle (2θ) 15

7.3 Selecting optimum conditions for detectors 15

7.4 Selecting optimum tube voltage and current 15

7.5 Selecting minimum measuring times 15

7.6 Selecting calibration samples 15

7.7 Selecting drift control and recalibration samples 16

7.8 Measuring the calibration samples 16

7.9 Regression calculations 16

8 Method validation (accuracy and precision) 16

9 Performance criteria 17

9.1 General 17

9.2 Precision test 17

9.3 Performance monitoring 17

9.4 Maintenance 17

10 Radiation protection 18

Annex A (informative) Example of calculating background equivalent concentration, limit of detection, limit of quantification and lower limit of detection 19

Annex B (informative) Example of calculating line interference of one element to another 21

Annex C (informative) Example of performance criteria obtained under repeatability conditions 22

Bibliography 23

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights This document supersedes EN 15063-1:2006

Within its programme of work, Technical Committee CEN/TC 133 requested CEN/TC 133/WG 10 “Methods of analysis” to revise the following standard:

EN 15063-1:2006, Copper and copper alloys — Determination of main constituents and impurities by

wavelength dispersive X-ray fluorescence spectrometry (XRF) — Part 1: Guidelines to the routine method

This is one of two parts of the standard for the determination of main constituents and impurities in copper and copper alloys The other part is:

EN 15063-2, Copper and copper alloys — Determination of main constituents and impurities by wavelength

dispersive X-ray fluorescence spectrometry (XRF) — Part 2: Routine method

In comparison with EN 15063-1:2006, the following changes have been made:

a) Definition 3.1 and 3.2 modified;

b) Clause 5 modified;

c) Editorial modifications have been made

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom

Introduction

Wavelength dispersive X-ray fluorescence spectrometry (XRF) has been used for several decades as an important analytical tool for production analysis XRF is characterised by its speed and high precision over a wide concentration range and as the XRF-method in most cases is used as a relative method, the limitations are often connected to the quality of the calibration samples The technique is well established and most of the physical fundamentals are well known

This guideline is intended to be used for the analysis of copper and copper alloys but it may also be applied to other materials

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply

a statement of metrological traceability

[SOURCE: ISO GUIDE 30:1992/Amd.1:2008, definition 2.2]

drift control samples

series of homogeneous materials that contain all the elements which have been calibrated and that cover the low, mid and high points of the calibration range for each element, used to detect variations over time in these points

Note 1 to entry: Drift control samples can also be used for statistical process control (SPC) of the instrument

3.6

recalibration samples

samples at both low and high points in the calibration ranges used to recalibrate the spectrometer

Note 1 to entry: These samples are measured during the calibration procedure and the intensities obtained are stored

in the computer according to the manufacturer's instructions

Note 2 to entry: No chemical analyses are necessary, but the homogeneity of these samples should be carefully evaluated

adjusting instrumental output to conform to the calibration

Note 1 to entry: To compensate for day to day instrumental variation, a set of recalibration samples are measured at the minimum low concentration and at a high concentration for each element (two-points recalibration) The measured intensities are compared to the initial measured intensities stored during the calibration procedure and the recalibration coefficients are calculated Calibration constants are not changed

3.9

reference measurements

measurements carried out to determine intensities for reference materials

Note 1 to entry: Initial intensities for the reference materials are stored during the calibration procedure and the intensities are updated to compensate for day to day variations

background equivalent concentration

concentration of analyte, which, when it is excited, provides a net intensity equal to the spectral background

Note 1 to entry: See Annex A

lower limit of detection

calculated minimum concentration based on counting statistical error at which the signal generated by a given element can be positively recognised, with a specified confidence level, above any background signals

Note 1 to entry: See Annex A

3.14

limit of quantification

smallest concentration that can be determined with a specified confidence level related to the limit of detection

by a factor dependent on the method

Note 1 to entry: See Annex A

3.15

sensitivity

rate of change of signal with change in concentration

Note 1 to entry: See Annex A Sensitivity is expressed as counts per second percent, and derived by difference in signals between a sample with a high concentration and one with a low concentration divided by the difference in concentrations

4 Instrumentation

4.1 Principles of X-ray fluorescence spectrometers

The principles of two different X-ray fluorescence spectrometer concepts are shown in Figures 1 and 2 Each detail is described in the following sub-clauses

Key

2 Primary collimator 6 Counter

3 X-ray tube 7 Secondary collimator

4 Test sample

Figure 1 — Plane crystal spectrometer geometry, used in sequential instruments

Key

Different high purity elements such as Rh, Ag, W, Cr or Au are used as anode materials For analysing copper and copper alloys, rhodium is usually used as the anode material in a multipurpose tube as it provides good excitation conditions for all elements of interest If possible, the anode material should not be the same as the element to be determined

Table 1 — Comparison between end-window and side-window tubes

Cooling Two cooling circuits

a) Direct cooling with deionised water b) Indirect cooling with tap water

One cooling circuit Direct cooling with tap water

Window Slight thermal stressing:

Table 2 — Anode materials for X-ray tubes and corresponding fields of application

Rh Good excitation conditions for elements with a low or high atomic number

Cr Good excitation conditions for elements with a low atomic number, especially

for K, Ca and Ti Not so good for elements with a high atomic number

Mo Good excitation conditions for elements with a high atomic number, especially

for Rb and Sr

W Good excitation conditions for elements with a high atomic number, especially

for Fe and Ni

Au Good excitation conditions for elements with a high atomic number, especially

for Cu and Zn

Ag Equivalent to Rh Ag is used if Rh lines interfere with element of interest

Double anode Different applications according to the anode materials

The X-ray tube produces a continuous spectrum and characteristic spectra depending on the selected anode material For optimum excitation, a maximum excitation energy lying at least two to three times above the corresponding absorption edge of the element line to be measured, is recommended

Equipment is available which may be operated with acceleration voltages up to 100 kV and with a maximum power of 3 kW The applicability of the apparatus is derived from either the high-voltage supply or the X-ray tube used Using acceleration voltages above 60 kV is only advantageous in a few cases, e.g to determine traces of elements with a high atomic number

The fluorescence arising inside a test sample is emitted uniformly in all directions Only a fraction reaches the test sample surface The proportion of the fluorescence measured depends on the angle between the test sample surface and the spectrometer The nearer to perpendicular the beam of radiation is to the test sample, the deeper the layers of the test samples that are measured

4.3 Vacuum system

The test sample is placed in the spectrometer chamber to be measured To analyse copper and copper alloys

it is recommended, for all elements, to measure under vacuum, to maintain stable conditions in the instrument A pressure of 13 Pa or less, controlled to ± 3 Pa is required

4.4 Test sample spinner

Most instruments are equipped with a test sample spinner to avoid effects of inhomogeneities, e g grinding striations If not, the test sample shall be orientated so that the relation between the X-ray beam and the inhomogeneities is always the same from measurement to measurement

4.5 Filters

If the element to be determined is the same as the anode material, a filter has to be put in front of the exit window of the tube to eliminate the characteristic lines The efficiency of a filter depends on its material and thickness A filter made of titanium or aluminium is often used to eliminate the characteristic lines from a chromium anode When a filter is used, the sensitivity for the element of interest will significantly decrease Sometimes a filter can be used to increase the peak to background ratio for low concentrations of elements with a high atomic number Many instruments are supplied with a filter changer containing filters of different materials and thicknesses

4.6 Collimators of slits

In a plane crystal geometry (Figure 1), only a portion of the secondary radiation is selected by a primary collimator and the parallel beam is allowed to penetrate the plane surface of the crystal The resolution of the spectrometer is affected not only by the crystal used, but also by the collimation of the radiation The finer the collimator selected, the better the resolution, but the intensity measured is lower Most sequential spectrometers of this type are supplied with at least two collimators: coarse and fine

In a curved crystal geometry (Figure 2), using collimators is not necessary as the radiation is focussed on the detector by a slit system

4.7 Analysing crystals

Analysing crystals are flat or curved with optimised capability for diffraction of the wavelength of interest

In order to isolate individual characteristic lines emitted by the test sample, large single crystals are used as dispersion media To cover the usual wavelength range between 0,2 Å and 15 Å, crystals with different

spaces between the atomic layers (d-value) are used Commonly used analysing crystals are listed in Table 3 for measuring the Kα-lines of particular elements To cover the whole wavelength range, a minimum of three

crystals is required; LiF(200), PET and TlAP or a multi-layer crystal for elements with a low atomic number

Table 3 — Crystals and their fields of application

Lithium fluoride (LiF) 200 0,402 7 K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr

Ammonium dihydrogen phosphate

Thallium hydrogen phtalate (TlAP) 100 2,575 F, Mg, Na, Al

Synthetic multi-layer crystal

a Atomic number

A typical set of crystals used for the analysis of copper and copper materials is shown in Table 4

Table 4 — Typical set of crystals for the analysis of copper and copper alloys

All counters can record only a limited number of pulses per unit of time because the measuring process for each pulse requires a fixed amount of time, which is in the order of 1 µs to 100 µs Other pulses cannot be

detected in this time, which is defined as dead time τ Therefore, care shall be taken to ensure that the

maximum pre-set pulse rate is not exceeded This is possible, for example, by connecting attenuation filters (simultaneous equipment) or decreasing the tube current Otherwise, there will be no linearity between the

NOTE Normally the number of pulses (counts) is indicated as kilocounts per second (Kc/s)

The dead time of the counters may have an effect from a pulse rate of approximately 105 pulses per second, however, higher pulse rates may be used if correction is applied

The counters used register pulses at different intensities as a function of the energy of the X-ray radiation Therefore, specific pulses or energies may be filtered out by selecting an electronic “window” (Pulse Height Discriminator), as pulse height discrimination eliminates interference pulses

4.9 Simultaneous and sequential Instruments

X-ray fluorescence instruments can be subdivided into two categories: simultaneous and sequential Simultaneous instruments have several fixed goniometers (channels) arranged around the test sample so that the individual element lines can be measured at the same time with the same excitation conditions Each channel is optimised for each element In sequential instruments, the user has the flexibility to optimise the measuring conditions independently for all selected elements and their backgrounds The goniometer can be set to a pre-defined angle (5° to 150°) and the excitation conditions can be optimised separately for all elements

Simultaneous instruments are often used in a production environment where speed is important and the sample matrix is known In modern instruments sequential and simultaneous functions can be combined

5 Sampling and test sample preparation

Test sample preparation is a critical procedure The test sample required is a flat solid with a diameter of at least 25 mm, and thickness of at least 1 mm, prepared from a sample obtained directly from a melt by pouring the liquid metal rapidly in an appropriately designed mould The test sample is prepared on a milling machine, without any other mechanical treatment (grinding, etc.) Chips or small pieces of pure copper may be transformed into a suitable test sample by remelting under an inert gas atmosphere followed by the same operations as above

NOTE Remelting copper alloys will lead to losses of elements, e.g Zn, Be, Pb

The measuring surface should be free of defects

6 Evaluation methods

6.1 General

Measure the intensities of secondary X-rays produced at the selected characteristic wavelengths and apply corrections as described in 6.2 to 6.5

6.2 Dead time correction

The dead time τ, is a function of a type of counter and can be calculated from the following approximate relationship between the measured pulse rate n, and the corrected pulse rate, n0

The dead time τ is generally around 2 µs With current types of spectrometers, dead time losses are often

compensated by means of a built-in correction circuit If this is not the case, they can be determined by repeatedly measuring the same test sample at a constant high voltage and with different current settings or by

measuring the ratio of IKα/IKβ, which is constant